Problem 6: The average weight of three man A, B and C is 84 kgs. A fourth man D joins them, and then average weight of the four becomes 80 kgs. If E , whose weight is 3 kgs more than that of D, replaces A. Then average weight of B, C, D and E becomes 79 kgs. Find weight of A.
Problem 6: The average weight of three man A, B and C is 84 kgs. A fourth man D joins them, and then average weight of the four becomes 80 kgs. If E , whose weight is 3 kgs more than that of D, replaces A. Then average weight of B, C, D and E becomes 79 kgs. Find weight of A.
a)70 kgs b) 80 kgs c) 75 kgs d) 72 kgs
Solution:
Let their be four persons and their weights be A, B , and D
As per statement average weight of A, B and C is 84 kg;
After joining of 4th person their average weight becomes 80, i-e;
Put value of A+B+C from eq (1);
Now let another person E (whose weight is 3 kg more than D’s weight i-e E =D+3) replaces A– then by statement of problem
Average weight becomes 79;
But ,
Put E=71 and D=68 in above;
put value of B+C in eq (1);
So, A=75 Kgs
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